Why Do Speedometer Needles Bounce?

[MADSTER]

My speedo needle just started bouncing...and I can hear a little "thrum thrum thrum" going on behind the gauge face.

Does it from 1MPH up to about 35MPH, up and down, then settles out until the speed drops back to 35.

Why does it do that? What's the fix?

Thanks for the help!!!

 

[4X4HIGH]

It's one of two things, either a cable going bad or dry, or the speedo head is going bad. Nothing else will cause it to bounce.

 

[MADSTER]

Thanks! When you say dry, do you mean it needs lubed?

If the head is going bad, that's the section that plugs into the tranny, right?

Sorry for all the questions...I've never owned an old Blazer before!

Gonna have to RTFM and get the old service manual out! LOL

 

[VikingWarlord]

Depending on how cold it is there now, I would replace the cable soon. My parents burb had the same problem a few years back only when it was cold and it actually made the needle go 360 degrees taking more than half the needle off when it did. I replaced the cable and it stopped but the damage had been done.

 

[4X4HIGH]

Yes the cable needs to be lubed. There is a product called Kable-ease. When i say speedo head i'm talking about the actuall speedometer.

 

[muddermilitia]

I got this same problem on my tow rig, guess it will be a good excuse to do that dash mod while its out

 

[vortec]

it bounces because it's all gangsta and stuff, g.

back to reality...a bind in the cable can make it do that, too. the most common cause i've seen for that is someone replacing the cable with one that is too short and so it have to make sharper turns instead of nice gradual arcs.

 

[MADSTER]

Hey, thanks guys! Good info!

I'll get out my service manual and figure it out from here. I do have to replace some lights in the dash as well so this will be a good time to do it all.

Again, I really appreciate the help!!!

Michael

 

[obijuan]

check out the mod to spray paint your bexel thing silver to get brighter dash illumination.

 

[MADSTER]

There's a mod here for painting the bezel or gauge faces silver for better visibility? Nice!!!

Anyone got the linky?

 

[k20]

No link, but get a can of the chrome spray paint from autozone, when you take out the gauge bezel & gauges, paint all the blue plastic with the chrome paint, especially the one piece that goes over the outside of the guages, thin plastic, black on one side blue on the other, that is what reflects the light onto the gauge faces. It will reflect light 10x better so you can actually see the gauges. I have white face gauges, and it made them actually look white at night instead of a greenish color.

 

[MADSTER]

aha! Thanks, k20. That's very helpful!

 

[muddermilitia]

yea thats the mod I was talkin about in my previous post